Currently, many applications exist for providing tamper evident safety seals on the tops of bottles containing a variety of different products. Aluminum foil seals commonly are used for sealing such bottles containing petroleum products, food products, medicines, etc.. The aluminum foil seal is adhered to the upper end of the bottle neck, and the seal usually is formed from a liner comprising a laminate of aluminum bonded to a suitable polymer which may be induction heat sealed to the top of the bottle. Once the seal is in place, the seal insures that no foreign materials subsequently enter the bottle after it has been sealed and prior to its ultimate use. A second important purpose is that if tampering is attempted, the seal must be altered or destroyed because access to the interior of the bottle cannot be accomplished without doing this.
While such tamper evident seals serve the intended purpose of protecting the bottle contents from unauthorized access, they are difficult to remove. Generally, it is necessary to use a knife or other sharp object to break the seal and tear it away from the edge of the bottle neck. This usually leaves a ragged opening around the edge of the bottle and sometimes results in a spilling of some of the contents of the bottle during the efforts to remove the seal.
U.S. Pat. No. 4,754,890 to Ullman discloses a seal and a machine for making it which forms a tab or protuberance on the edge of the seal. This tab projects upwardly from the seal when the cap is removed from the top of the bottle. The tab then may be grasped by the user to peel the seal off the top of the bottle. The tab and seal formed by the device of the Ullman Patent are formed in a single punch operation, but it is necessary first to fold the foil material under itself along both edges prior to the punch operation. The punch then extends past this folded portion to form a folded under tab at the time the cap insert is made. Thus, it is necessary to provide separate apparatus to fold under the edges of the foil strip from which the seals are formed. A problem also exists in maintaining the precise alignment necessary to insure that the tab is not cut off and that it is of sufficient strength to prevent it from being torn away when the seal is to be removed from the bottle. In addition, forming the tab in this manner causes a flat edge to be also formed on the seal itself, which limits the size of the tab which can be formed. It is difficult to maintain the necessary alignment to overcome these problems.
Two other patents which disclose the need for providing a pull tab on a membrane cover over the opening in a metal can, are the Hardt U.S. Pat. No. 4,328,905 and Wright et al. U.S. Pat. No. 4,544,080. Neither of these patents, however, disclose the manner in which the tabs are formed.
Another technique which has been employed is to utilize progressive dies to first form a tab from a sheet of liner material passing through the liner insert machine. The tab is punched at a first position with a tab punch; and as the liner advances, the tab is folded under the liner material. This punched-folded tab then advances to the liner punch station where it is punched out as a part of the liner insert. Since the tab is folded under the insert, which then is inserted into a cap with the tab located between the cap and the liner, it subsequently can be utilized to remove the insert from a container on which the cap ultimately is attached. For a progressive die system of this type to work properly, the tab must be folded and creased without any defects, and then held folded until it reaches the liner insert punch station, alignment is tab is located at the liner insert punch station, alignment is critical. If the tab fold is not far enough into the punch station, the tab will be cut off. Also, if the tab is too far into the punch station, slits between the tab and the liner insert will result. These slits ultimately will cause the tab to tear away from the main liner insert when it is pulled to remove the insert from the container on which the insert ultimately is attached. This then leaves the main portion of the insert unremoved, with a rip or opening through it. Consequently, if significant precision is not maintained in such a progressive die system, faulty product results.
It is desirable to provide a cap-lining machine which produces pull tab liner insert disks which are not subject to the disadvantages of the prior art. Ideally, it is desirable to provide a one-step punch and die and insert operation to produce a tab liner insert seated in a cap, all as part of a single machine operation.